Electronic Ign. Control Unit (ECU) Heat condition

All,
I am troubleshooting a hot-start problem on another thread in this forum section, and during my time under the hood, I have noticed that my ECU gets REALLY hot after only about 10-mins of driving? (By HOT, I mean it will burn your fingers like if you touched the engine block.) Is this normal? Could a failing/hot ECU in ANYWAY impact the ignition signals being sent to the ignition relay and hence affect hot-cranking?
BACKGROUND: My car is a 1974 Duster 360 (originally a slant-6 car) with OEM style electronic ignition system. I have been troubleshooting hot-starting problems since I bought the car about 2-years ago that I describe in details in another post. In summary: with a OEM style starter, I'd get a lot of chatter and VERY slow cranking from the starter whenever the engine was hot (5-10 mins of driving). This starter looked to be well-used and was contacting a header pipe so I opted to do the following: a) changed to a high-torque mini-starter, b) crimped the closest header pipe for more clearance and wrapped starter with a heat shield, c) checked all battery cables fm trunk to engine bay & cleaned/re-fit all connections, d) upgraded to a red-top Optima battery, & e) installed a new ignition relay.
NOW: I get absolutely NOTHING(no noise/clicks at all) when I try to start a hot engine but, after the engine cools for a while, the starter will chatter and crank slowly. After fully cooling off(35-45mins), it cranks strong and fires up instantly... Any help is appreciated.